It is known that a pressure cooker usually comprises a container and a lid. Both the container and lid are provided with radial handles for lifting purposes. The lid is further provided with a central pressure relief valve and with a safety valve which is intended to relieve the pressure in the event that the relief valve, for some reason or other, fails to operate.
The aforementioned safety valve is usually comprised by a rubber plug located in a corresponding aperture formed in the lid, the plug being expelled when the pressure rises beyond a specified value that is understood as being safe.
No matter how widely used this type of safety valve is, it is still not altogether satisfactory because the aforementioned rubber plug will harden after a certain period of service. The pressure required to expel the hardened rubber plug is beyond that which is understood as being safe. Additionally, upon being expelled, the rubber plug is ejected with extreme violence endangering the user of the pressure cooker. Further, following ejection of the plug the aperture is open enabling the product being cooked to be expelled therethrough in such a manner as to stain the ceiling, stove, adjoining walls and floor.
A further inconvenience associated with this type of safety valve is that the aforementioned plug is a very slow-moving article from a marketing standpoint. This means that the specialized home applicance stores are seldom inclined to carry stocks of the plug. Accordingly, the users of pressure cookers incorporating this type of safety valve run into extreme difficulties when faced with the need to replace the plug.